Vaporizer for vaporizing a constituent of a plant material

ABSTRACT

Apparatus and methods are described for use with a vaporizer that vaporizes at least one active ingredient of a plant material. In response to receiving a first input to the vaporizer, the plant material is heated, in a first heating step. An indication of the temperature of the plant material is detected, and, in response to detecting an indication that the temperature of the plant material is at a first temperature, the first heating step is terminated, by withholding causing further temperature increase of the plant material. The first temperature is less than 95 percent of the vaporization temperature of the active ingredient. Subsequently, a second input is received at the vaporizer. In response thereto, the plant material is heated to the vaporization temperature, in a second heating step. Other applications are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. § 120 of U.S.application Ser. No. 16/372,816, filed Apr. 2, 2019, which is adivisional under 35 U.S.C. § 121 of U.S. application Ser. No.16/227,026, filed Dec. 20, 2018, which is a divisional under 35 U.S.C. §121 of U.S. application Ser. No. 14/662,607, filed Mar. 19, 2015, theentire contents of each of which are incorporated herein by reference.

FIELD

Some applications of the present invention generally relate to medicalapparatus. Specifically, some applications of the present inventionrelate to vaporizers for the delivery of an active ingredient to asubject.

BACKGROUND

Medical use of Cannabis and its constituent cannabinoids, such astetrahydrocannabinol (THC) and cannabidiol (CBD), has a long history. Inmodern times, Cannabis is used by patients suffering from AIDS, orundergoing chemotherapy treatment, in order to relieve nausea andvomiting associated with their conditions. Cannabis is also used in amedicinal manner in order to provide pain relief, to treat musclespasticity, and to stimulate appetite.

Medicinal Cannabis can be administered using a variety of methods,including vaporizing or smoking dried buds, eating extracts, takingcapsules or using oral sprays. The legality of medical use of Cannabisvaries internationally. However, even in countries in which the medicaluse of Cannabis is legal, the provision of Cannabis to such users ishighly regulated, and it is the case that in almost all Westerncountries, recreational use of Cannabis is illegal.

SUMMARY

In accordance with some applications of the present invention, avaporizer is used to vaporize the active ingredient of a plant material,by heating the plant material. For example, the vaporizer may be used tovaporize the constituent cannabinoids of Cannabis (e.g.,tetrahydrocannabinol (THC) and/or cannabidiol (CBD)). Alternatively oradditionally, the vaporizer may be used to vaporize tobacco, and/orother plant or chemical substances that contain an active ingredientthat becomes vaporized upon the substance being heated.

Typically, the vaporizer houses a plurality of capsules, each of thecapsules including a given amount of a plant material that contains anactive ingredient. For some applications, the vaporizer is shaped todefine first and second receptacles, each of which is shaped to housethe plurality of capsules in stacked configurations. While each of thecapsules is disposed at a vaporization location within the vaporizer, aheating element causes the active ingredient of the plant materialwithin the capsule to become at least partially vaporized byindividually heating the capsule. For some applications, the heatingelement includes one or more electrodes that heat the capsule viaresistive heating, by driving a current into a portion of the capsule(e.g., into a metallic mesh of the capsule), or driving a current intoan internal heating element that is housed within the vaporizer.Typically, a capsule-transfer mechanism of the vaporizer individuallytransfers each of the capsules from the first receptacle to thevaporization location and from the vaporization location to the secondreceptacle.

For some applications, a two-step heating process is applied to theplant material, as follows. In response to receiving a first input atthe vaporizer, a first heating step is initiated. The first heating stepis terminated, and further heating of the plant material is withheld, inresponse to detecting an indication that the temperature of the plantmaterial has reached a first temperature that is typically less than 95percent of a vaporization temperature of the active ingredient.Subsequently, in response to receiving a second input at the vaporizer(e.g., in response to detecting that a user is inhaling from thevaporizer, or in response to the user pressing a button) the plantmaterial is heated to the vaporization temperature of the activeingredient, in a second heating step.

Typically, the first heating step is performed at a faster heating ratethan the second heating step. For some applications, by performing theheating in the two-stage process as described, one or more of thefollowing results are achieved:

1) By withholding the first (rapid) stage of the heating in response tothe temperature of the capsule reaching less than 95 percent of thevaporization temperature, even if the heating overshoots, the plantmaterial is not pyrolyzed, since the plant material is not heated to atemperature that is greater than the pyrolysis temperature.

2) Since the second stage of the heating is performed slowly, there isnegligible overshooting in the second stage of the heating process, andtherefore the plant material does not get pyrolyzed in the second stageof the heating process.

3) Since, during the first stage of the heating, the plant material hasalready been heated to a temperature that is relatively close thevaporization temperature, even though the second stage of the heating isslow, the time that is required to heat the plant material to thevaporization temperature, from the initiation of the second heatingstage, is relatively short (e.g., less than two seconds).

4) Due to low heat conduction of the plant material, if the plantmaterial is heated rapidly, this can give rise to non-uniform heating ofthe plant material. This can cause some portions of the plant materialto be pyrolyzed, and/or other portions of the plant material not to bevaporized. By withholding further heating of the plant material afterthe first temperature has been reached, and until the second input isreceived, heat is able to dissipate through the plant material (duringthe interim period between the first and second heating stages) beforeany portion of the plant material has been heated to the vaporizationtemperature. Furthermore, since the temperature increase during thesecond stage is relatively small, the temperature increase is able todissipate through the plant material relatively quickly. Thus,relatively uniform heating of the plant material is achieved, such thatmost of the active ingredient within the plant material is vaporized,while there is substantially no pyrolysis of the plant material.

There is therefore provided, in accordance with some applications of thepresent invention, a method for use with a vaporizer that vaporizes atleast one active ingredient of a plant material, the method including:

receiving a first input at the vaporizer;

in response to receiving the first input, heating of the plant material,in a first heating step;

detecting an indication of a temperature of the plant material;

in response to detecting an indication that the temperature of the plantmaterial is at a first temperature, terminating the first heating step,by withholding causing further temperature increase of the plantmaterial, the first temperature being less than 95 percent of avaporization temperature of the active ingredient;

subsequently, receiving a second input at the vaporizer; and

in response to receiving the second input, heating the plant material tothe vaporization temperature of the active ingredient, in a secondheating step.

For some applications, detecting the indication of the temperature ofthe plant material includes detecting the indication of the temperatureof the plant material using an optical temperature sensor.

For some applications, the method further includes generating anindication that the first heating step has terminated.

For some applications, terminating the first heating step, bywithholding causing further temperature increase of the plant materialincludes preventing pyrolysis of the active ingredient.

For some applications, the method further includes, subsequent to thesecond heating step, in response to detecting that no air has beeninhaled from the vaporizer for a given time period, reducing atemperature of the plant material to below the vaporization temperatureof the plant material.

For some applications, the method further includes detecting a rate ofair flow through the vaporizer by detecting an indication of an amountof energy required to maintain the temperature of the plant materialconstant.

For some applications, heating the plant material in the first heatingstep includes heating the plant material at a first heating rate,heating the plant material in the second heating step includes heatingthe plant material at a second heating rate, and the first heating rateis greater than the second heating rate.

For some applications, heating the plant material at the second heatingrate includes heating the plant material at a rate of less than 50degrees Celsius per second.

For some applications, heating the plant material at the rate of lessthan 50 degrees Celsius per second includes preventing pyrolysis of theactive ingredient.

For some applications, heating the plant material at the first heatingrate includes heating the plant material at a rate of more than 50degrees Celsius per second.

For some applications, heating the plant material at the first heatingrate includes heating the plant material at a rate of more than 100degrees Celsius per second.

For some applications, heating the plant material at the first heatingrate includes heating the plant material at a rate of more than 50degrees Celsius per second.

For some applications, heating the plant material at the first heatingrate includes heating the plant material at a rate of more than 100degrees Celsius per second.

For some applications, receiving the second input includes detectingthat a user is inhaling from the vaporizer.

For some applications, detecting that the user is inhaling from thevaporizer includes detecting the indication of the temperature of theplant material.

For some applications, detecting that the user is inhaling from thevaporizer includes detecting an indication of an amount of energyrequired to maintain the temperature of the plant material constant.

For some applications, the plant material includes Cannabis andterminating the first heating step includes withholding causing furthertemperature increase of the plant material in response to detecting anindication that the temperature of the plant material has reached atemperature that is less than 170 degrees Celsius.

For some applications, terminating the first heating step includeswithholding causing further temperature increase of the plant materialin response to detecting an indication that the temperature of the plantmaterial has reached a temperature that is less than 160 degreesCelsius.

For some applications, detecting the indication of the temperature ofthe plant material includes detecting a temperature of a capsule inwhich the plant material is housed.

For some applications, the capsule includes a metallic mesh, anddetecting the temperature of the capsule includes detecting electricalresistance of the mesh.

There is further provided, in accordance with some applications of thepresent invention, apparatus for use with a plant material that includesat least one active ingredient, the apparatus including:

a vaporizer configured to vaporize the active ingredient of the plantmaterial, the vaporizer including:

-   -   a heating element configured to heat the plant material;    -   a temperature sensor configured to detect an indication of a        temperature of the plant material; and    -   control circuitry configured to:        -   receive a first input;        -   in response to receiving the first input, drive the heating            element to heat the plant material at a first heating rate,            in a first heating step;        -   in response to receiving, from the temperature sensor, an            indication that the temperature of the plant material is at            a first temperature, terminate the first heating step, by            withholding causing further temperature increase of the            plant material by the heating element, the first temperature            being less than 95 percent of a vaporization temperature of            the active ingredient;        -   subsequently, receive a second input at the vaporizer; and        -   in response to receiving the second input, drive the heating            element to heat the plant material to the vaporization            temperature of the active ingredient at a second heating            rate that is less than the first heating rate, in a second            heating step.

For some applications, the control circuitry is configured to be removedfrom the vaporizer and to be coupled to a second vaporizer.

For some applications, the apparatus further includes a phase-changematerial that is coupled to the capsule, the phase-change material beingconfigured to undergo a phase change at a temperature that is below apyrolysis temperature of the plant material.

For some applications, the capsule includes at least one hollow wire,and the phase-change material is housed inside the hollow wire.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

a vaporizer shaped to define at least first and second receptacles, thevaporizer including:

-   -   a plurality of capsules, each of the capsules including a plant        material that contains an active ingredient, the first and        second receptacles each being shaped to house the plurality of        capsules in stacked configurations;    -   a heating element configured, while each of the capsules is        disposed at a vaporization location within the vaporizer, to        cause the active ingredient of the plant material within the        capsule to become at least partially vaporized by individually        heating the capsule; and

a capsule-transfer mechanism configured to individually transfer each ofthe capsules from the first receptacle to the vaporization location andfrom the vaporization location to the second receptacle.

For some applications, the capsule-transfer mechanism includes arotating capsule-transfer mechanism, configured to transfer the capsulesby rotating.

For some applications, the first and second receptacles and thevaporization location are linearly aligned with each other, and thecapsule-transfer mechanism includes a linear capsule-transfer mechanism,configured to move each of the capsules by moving linearly.

For some applications, the heating element includes one or moreelectrodes configured to heat the capsules via resistive heating, bydriving an electrical current into the portion of the capsule.

For some applications, each of the capsules includes one or moremetallic meshes, and the one or more electrodes are configured to heatthe capsules by driving the electrical current into the one or moremetallic meshes of the capsule.

For some applications, a width of the vaporizer is less than 9 cm. Forsome applications, a depth of the vaporizer is less than 6 cm. For someapplications, a height of the vaporizer is less than 20 cm.

There is further provided, in accordance with some applications of thepresent invention, a method including:

providing a vaporizer shaped to define at least first and secondreceptacles, a plurality of capsules being housed in a stackedconfiguration inside the first receptacle, and each of the capsulesincluding a plant material that contains an active ingredient;

using a capsule-transfer mechanism individually transferring a first oneof the capsules from the first receptacle to a vaporization locationwithin the vaporizer;

when the first capsule is disposed at the vaporization location withinthe vaporizer, causing the active ingredient within the plant materialwithin the first capsule to become at least partially vaporized byindividually heating the capsule; and

using the capsule-transfer mechanism individually transferring the firstcapsule from vaporization location to the second receptacle, the secondreceptacle being configured to house a plurality of the capsules in astacked configuration.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

a vaporizer including:

-   -   at least one capsule including:        -   upper and lower meshes; and

a given amount of a plant material housed between the upper and lowermeshes, the plant material containing at least one active ingredient;

-   -   control circuitry; and    -   first, second, third and fourth electrodes,    -   the control circuitry being configured to vaporize the at least        one active ingredient of the plant material by:        -   driving a current from the first electrode to the second            electrode via the lower mesh, and        -   driving a current from the third electrode to the fourth            electrode via the upper mesh.

There is additionally provided, in accordance with some applications ofthe present invention, a method including:

-   -   providing a capsule that includes upper and lower meshes, and a        given amount of a plant material housed between the upper and        lower meshes, the plant material containing at least one active        ingredient; and    -   vaporizing the at least one active ingredient of the plant        material by:        -   driving a current from a first electrode to a second            electrode via the lower mesh, and        -   driving a current from a third electrode to a fourth            electrode via the upper mesh.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

a vaporizer including:

-   -   at least one capsule, the capsule including a plant material        that contains at least one active ingredient;    -   a heating element configured, to cause the active ingredient        within the plant material within the capsule to become at least        partially vaporized by heating the capsule; and

a vibrator configured to vibrate the capsule.

For some applications, the vibrator includes a vibrator selected fromthe group consisting of: a vibration motor, a piezo-electric crystal, asonic vibrator, and an ultrasonic vibrator.

For some applications, the vibrator is configured to increase airflowthrough the capsule by vibrating the capsule.

For some applications, the vibrator is configured to mix the plantmaterial within the capsule by vibrating the capsule.

For some applications, the vibrator is configured to increase auniformity of heating of the plant material within the capsule byvibrating the capsule.

There is additionally provided, in accordance with some applications ofthe present invention, a method including:

providing a vaporizer that includes at least one capsule, the capsuleincluding a plant material that contains at least one active ingredient;

activating a heating element within the vaporizer to cause the activeingredient within the plant material to become at least partiallyvaporized by heating the capsule; and

activating a vibrator within the vaporizer to vibrate the capsule.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood from the followingdetailed description of embodiments thereof, taken together with thedrawings.

FIGS. 1A-C are schematic illustrations of respective views of theexterior of a vaporizer, in accordance with some applications of thepresent invention;

FIGS. 2A-B are exploded views of the vaporizer of FIGS. 1A-C, inaccordance with some applications of the present invention;

FIG. 3A is a top view and FIGS. 3B-D are respective cross-sectionalviews of the vaporizer of FIGS. 1A-C, in accordance with someapplications of the present invention;

FIGS. 4A-D are schematic illustrations of respective views of a capsulethat contains plant material that includes an active ingredient, inaccordance with some applications of the present invention;

FIG. 5 is a schematic illustration of electrodes of the vaporizer incontact with a mesh of a capsule that contains plant material thatincludes an active ingredient, in accordance with some applications ofthe present invention;

FIGS. 6A-D are schematic illustrations of respective configurations ofthe electrodes of the vaporizer, in accordance with some applications ofthe present invention;

FIGS. 7A-B are schematic illustration of respective views of a vaporizerthat includes a linear capsule-transfer mechanism, in accordance withsome applications of the present invention; and

FIG. 8 is a graph illustrating a technique for heating plant materialusing a vaporizer, in accordance with some applications of the presentinvention.

DETAILED DESCRIPTION

Reference is now made to FIGS. 1A-C, which are schematic illustrationsof respective views of the exterior of a vaporizer 20, in accordancewith some applications of the present invention. Typically, vaporizer 20is used to vaporize the active ingredient of a plant material. Forexample, vaporizer 20 may be used to vaporize the constituentcannabinoids of Cannabis (e.g., tetrahydrocannabinol (THC) and/orcannabidiol (CBD)). Alternatively or additionally, the vaporizer may beused to vaporize tobacco, and/or other plant or chemical substances thatcontain an active ingredient that becomes vaporized upon the substancebeing heated.

Vaporizer 20 includes a main body 22, which houses capsules and controlcircuitry of the vaporizer, as described in further detail hereinbelow.The control circuitry is configured to act as a control unit, whichcontrols the functioning of the vaporizer. Typically, the vaporizeradditionally includes a top cover 24, from which a mouthpiece 26protrudes. During use, the user typically inhales the vaporized activeingredient via the mouthpiece.

Typically, vaporizer 20 is configured to be portable and, during use,the vaporizer is configured to be held in a single hand of a user. Thedimensions of the vaporizer are typically as follows:

-   -   A height H1 of main body 22 of the vaporizer (excluding        mouthpiece 26) is typically more than 8 cm (e.g., more than 10        cm), and/or less than cm (e.g., less than 12 cm), e.g., between        8 cm and 15 cm, or between 10 and 12 cm.    -   A height H2 of mouthpiece 26, is typically more than 2 cm (e.g.,        more than 2.5 cm), and/or less than 6 cm (e.g., less than 3.5        cm), e.g., between 2 cm and 6 cm, or between 2.5 and 3.5 cm.    -   Typically, the total height of the vaporizer, including the        mouthpiece is less than 20 cm, e.g., less than 15 cm.    -   A width W1 of the vaporizer is typically more than 3 cm (e.g.,        more than 4 cm), and/or less than 9 cm (e.g., less than 6),        e.g., between 3 cm and 9 cm, or between 4 cm and 6 cm.    -   A depth D1 of the vaporizer is typically more than 2 cm (e.g.,        more than 3 cm), and/or less than 6 cm (e.g., less than 5),        e.g., between 2 cm and 6 cm, or between 3 cm and 5 cm.

For some applications, a capsule-transfer wheel 28 is disposed on theoutside of the top cover. The capsule-transfer wheel controls acapsule-transfer mechanism 44 (FIG. 2A). As described in further detailhereinbelow, the capsule-transfer mechanism is configured to (a)individually transfer unused capsules from a first receptacle 40A (FIG.2A) within the main body of the vaporizer to a vaporization location 46(FIG. 2A), at which the capsule is heated such as to vaporize the activeingredient, and (b) to individually transfer used capsules from thevaporization location to a second receptacle 40B (FIG. 2A) within themain body of the vaporizer. For some applications, the capsule-transfermechanism is a rotatable mechanism, e.g., a rotatable disc, as shown inFIGS. 2A-B. For some such applications, the capsule-transfer wheel isturned by a user in order to control the rotatable capsule-transfermechanism. Alternatively or additionally, the rotatable capsule-transfermechanism (or any other capsule-transfer mechanism described herein) iscontrolled by an electric motor (not shown).

For some applications, a removable back cover 30 is disposed upon mainbody 22 of vaporizer 20. As shown, for some applications, the back coverdefines a grill 32. Grill 32 is configured to allow airflow into themain body of the vaporizer, as described in further detail hereinbelow.

For some applications, the inner surface of mouthpiece 26 (and/or otherportions of the vaporizer) includes a lipophobic or hydrophobic coating27 that is configured to prevent products of the vaporization of theactive ingredient from sticking to the inner surface of the mouthpiece.Alternatively or additionally, electrical charge is driven onto surfacesof the vaporizer (such as the inner surface of mouthpiece 26), such thatthe charge accumulates on the surfaces and repels products of thevaporization of the active ingredient from the surfaces.

Reference is now made to FIGS. 2A-B, which are exploded views ofvaporizer 20, in accordance with some applications of the presentinvention.

Referring to FIG. 2A, typically, vaporizer 20 includes first and secondreceptacles 40A and 40B, which are configured to house capsules 42,which include a plant material that contains an active ingredient.Unused capsules are typically housed in a stacked configuration insidethe first receptacle, and used capsules are housed in a stackedconfiguration inside the second receptacle.

Capsule-transfer mechanism 44 is configured to transfer the capsulesform the first receptacle to the second receptacle. For someapplications, the capsule-transfer mechanism is a rotatablecapsule-transfer mechanism (e.g., a rotatable disc), as shown in FIG.2B. Typically, the capsule-transfer mechanism is configured to (a)individually transfer unused capsules from first receptacle 40A tovaporization location 46 at which the capsule is heated such as tovaporize the active ingredient, and (b) to individually transfer usedcapsules from the vaporization location to second receptacle 40B.

For some such applications, vaporizer 20 includes one or more heatingelements, which are configured to heat the plant material within thecapsule (such as to vaporize the active ingredient within the plantmaterial). For some applications, electrodes 48 are configured to act asheating elements, by heating the plant material within the capsule, bydriving an electrical current into capsule 42. For some applications,capsule 42 includes one or more metallic meshes 84 (FIG. 4A). Theelectrodes heat the plant material by heating the one or more meshes viaresistive heating, by driving a current into the one or more meshes.Alternatively or additionally, the electrodes heat an internal heatingelement that is housed within the vaporizer, by driving a current intothe internal heating element. Typically, the electric current that isdriven is fixed, such that, for example, the heating of the capsules isnot affected by variations in the degree of contact between theelectrodes and the meshes of the capsules.

For some applications, a spring 49 with a pushing element 51 is disposedunderneath a portion 25 of top cover 24. The spring is configured topush the used capsules into second receptacle 40B.

For some applications, a portion of capsule 42 is coated or filled witha phase-change material 47. The phase-change material is selected suchas to maintain the capsule below the pyrolysis temperature of the plantmaterial, and thereby prevents the plant material from being pyrolyzed.For example, the phase-change material may undergo a solid-to-liquidphase change at a temperature that is between the vaporizationtemperature and the pyrolysis temperature of the plant material, suchthat the phase-change material absorbs heat as latent heat of fusion atthis temperature. For some applications, a portion of the vaporizer(e.g., vaporization location 46, receptacle 40A and/or receptacle 40B)is coated with phase-change material 47.

Referring now to FIG. 2B, typically, a power supply 50 (e.g., a battery)and control circuitry 52 are housed inside the main body of vaporizer20. Typically, the power supply and/or the control circuitry are coupledto the main body of the vaporizer by a coupling element 53, such as anadhesive, a screw, a clip, and/or a pin. For some applications, thecontrol circuitry is configured to drive a current into the capsule viaelectrodes 48, using power supplied by the power supply.

For some applications, back cover 30 is removable and reusable, andcontrol circuitry 52, power supply 50, and/or temperature sensor 54 arecoupled to the back cover (e.g., by being housed in the back cover).Typically, for such applications, after all of the capsules in thevaporizer have been vaporized, the back cover is removed, together withthe components that are coupled to the back cover. The back cover andthe components are then transferred and coupled to a different vaporizerthat includes unused capsules.

For some applications, vaporizer 20 includes a temperature sensor 54that is configured to measure an indication of the temperature of theplant material that is being heated, e.g., by measuring the temperatureof the capsule that is being heated. For example, the temperature sensormay be an optical temperature sensor, such as an infrared temperaturesensor, that is configured to measure the temperature of the capsulewithout contacting the capsule. In this manner, the infrared temperaturesensor measures the temperature of the capsule, without affecting thetemperature of the capsule by drawing heat from the capsule. For someapplications, the temperature sensor is covered with a lipophobic orhydrophobic coating 56 that protects the temperature sensor fromproducts of the vaporization being deposited upon the temperaturesensor. For some applications, a different temperature sensor is used.For example, the control circuitry may detect the temperature of thecapsule by detecting changes in the resistance of components of thecapsule (e.g., mesh 84 of the capsule) using electrodes 48.

As described hereinabove, typically unused capsules are housed insidefirst receptacle 40A and used capsules are housed inside receptacle 40B.Typically, springs 58 and pushing elements 60 are coupled to a bottomcover 62 of the vaporizer. The springs and pushing elements areconfigured to maintain the stacked configurations of the capsules insidethe receptacles by pushing the capsules toward the top of the vaporizer.

Reference is now made to FIGS. 3A-D. FIGS. 3B-D are schematiccross-sectional views of vaporizer 20, in accordance with someapplications of the present invention. FIG. 3A is a top view ofvaporizer 20, in accordance with some applications of the presentinvention. FIG. 3A includes lines indicating the locations of thecross-sections that are shown, respectively, in FIGS. 3B, 3C, and 3D.

Referring to FIG. 3B, for some applications, vaporizer 20 includes avibrator 70 that is configured to vibrate capsule 42, while the capsuleis being heated. During use of the vaporizer, the user inhales viamouthpiece 26. This causes air to flow through grill 32 to themouthpiece via the capsule, as indicated by airflow arrows 72. Due tothe heating of the capsule, the active ingredient within the plantmaterial of the capsule is vaporized and is introduced into the air thatis flowing through the vaporizer. For some applications, by vibratingthe capsule, the vibrator reduces blockage of air flow through thecapsule, and/or increases airflow through the capsule relative to if thecapsule were not vibrated. For some applications, due the vibration ofthe capsule, a greater amount of the active ingredient vaporizes andenters the airflow than if the capsule were not vibrated. Alternativelyor additionally, vibration of the capsule improves the distribution ofheat across the capsule, and/or mixes the plant material within thecapsule.

In accordance with respective application, vibrator 70 includes avibration motor, a piezo-electric crystal, a sonic vibrator, anultrasonic vibrator, and/or a different type of vibrator. For someapplications, one or more parameters of the vibration applied by thevibrator is varied such as to increase the efficiency of the activeingredient vaporization, to increase airflow through the capsule, toreduce air flow blockage, to improve distribution of heat across thecapsule, and/or to mix the plant material within the capsule. Forexample, the frequency, the amplitude, and/or the direction of thevibration may be varied.

For some applications, vaporizer 20 includes a port 74 via which thevaporizer is connected to an external source of power and/or data input.For example, power supply 50 may be configured to be recharged byconnecting the vaporizer to an external power source via port 74.Alternatively or additionally, control circuitry 52 may receive data,e.g., programming instructions, via port 74.

For some applications, a healthcare professional (e.g., a pharmacist ora doctor) may input instructions into the control circuitry that controlthe heating rate that is applied for a given amount of air flow throughthe capsule. By controlling the heating rate per unit air flow, theamount of the active ingredient that is vaporized per unit airflowthrough the vaporizer may be controlled. Alternatively or additionally,the healthcare professional may input instructions into the controlcircuitry that control the amount of airflow through the vaporizer thatis permitted during each use of the vaporizer, and/or the amount ofairflow through the vaporizer that is permitted within a given timeperiod (e.g., per hour, or per day). In this manner, the healthcareprofessional may control the dosage of the active ingredient that theuser is able to receive during each use of the vaporizer, and/or withinthe given time period. For some applications, the control circuitry isconfigured to automatically determine the rate and/or volume of air flowthrough the vaporizer, as described in further detail hereinbelow.

Referring now to FIG. 3C, as shown, capsules 42 that are unused (i.e.,capsules, the active ingredient of the plant material of which has notbeen vaporized) are housed, in a stacked configuration (i.e., such thatwhen the vaporizer is in an upright orientation, the capsules arearranged one above the other), inside receptacle 40A. Used capsules arehoused, in a stacked configuration, inside receptacle 40B. As describedhereinabove, for some applications, springs 58 and pushing elements 60are coupled to a bottom cover 62 of the vaporizer and are configured tomaintain the stacked configurations of the capsules inside thereceptacles by pushing the capsules toward the top of the vaporizer. Forsome applications, by storing the capsules in stacked configurations,dimensions of the width and depth of vaporizer 20 may be such that thevaporizer can be comfortably held by a user (e.g., within a single handof the user).

Spring 49 and pushing element 51 typically push the used capsules intoreceptacle 40B, such that the used capsules are maintained below a planeof movement of capsule-transfer mechanism 44. In this manner, capsulesthat have been placed inside receptacle 40B remain inside receptacle40B, even when the capsule-transfer mechanism is moved.

For some applications, capsules 42 have circular cross-sections, andreceptacles 40A and 40B define cylindrical tubes that house thecapsules. Alternatively, capsules 42 may have a different shape, andreceptacles 40A and 40B may define hollow spaces that are shaped so asto conform with the shapes of the capsules.

With reference to FIG. 3D, as described hereinabove, for someapplications, temperature sensor 54 is an optical temperature sensor,such as an infrared temperature sensor, that is configured to measurethe temperature of the capsule without contacting the capsule. FIG. 3Dshows sensor 54 receiving beams 80 of optical light from capsule 42, thecapsule having been heated. Sensor 54 is configured to measure thetemperature of capsule 42, based upon the received light.

As shown in FIG. 3D, for some applications, electrode 48 includes atleast four electrodes 48A, 48B, 48C, and 48D. The plant materialcontained within the capsule is heated by driving a current from firstelectrode 48A to second electrode 48B via a lower mesh of capsule 42.Alternatively or additionally, plant material contained within thecapsule is heated by driving a current from third electrode 48C tofourth electrode 48D via an upper mesh of capsule 42. For someapplications, by heating the plant material in the aforementionedmanner, the plant material within the capsule is heated more uniformlythan if, for example, a monopolar electrode were to drive a current intoa location on the upper or lower mesh. For some applications, capsule 42includes an internal heating element (e.g., an internal mesh (notshown)), as an alternative or in addition to the upper and lower meshes.The internal heating element is configured to be heated in a similarmanner to that described with reference to the upper and lower meshes.

Reference is now made to FIGS. 4A-D, which are schematic illustrationsof respective views of capsule 42, the capsule containing plant material82 that includes an active ingredient, in accordance with someapplications of the present invention. As described hereinabove, forsome applications, the plant material is Cannabis, and the activeingredient is the constituent cannabinoids of Cannabis (e.g.,tetrahydrocannabinol (THC) and/or cannabidiol (CBD)). Alternatively oradditionally, the plant material may be tobacco, and/or other plant orchemical substances that contain an active ingredient that becomesvaporized upon the substance being heated.

For some applications, plant material 82 is housed between upper andlower metallic meshes 84. For some applications, each of the meshes hasopenings of more than 15 micron (e.g., more than 20 micron), and/or lessthan 80 micron (e.g., less than 50 micron), e.g., 15-60 micron, or 20-50micron. Typically the meshes are coupled to a central portion 86 of thecapsule (e.g., a central disc, as shown), the central portion defining ahole. For example, the meshes may be coupled to the central portion viaan adhesive 88, such as a high-temperature-resistant glue, ordouble-sided adhesive. Typically, the adhesive is configured such thatthe adhesive does not emit fumes, even when the adhesive is subjected toa high temperature, such as a temperature of greater than 200 degreesCelsius. Typically, the plant material is housed between the meshes andwithin the hole defined by the central portion of the capsule.

Typically, plant material 82 is ground, such that (a) the plant materialis in sufficiently small pieces that the material fits within thecapsule, and a large surface area of the plant material is exposed toair flow through the vaporizer (b) the pieces of the plant material aresufficiently large that they do not pass through the meshes, and (c) theactive ingredient retains its potency. For some applications, the plantmaterial is cryogenically ground and/or powderized, e.g., usingtechniques that are known in the art.

For some applications, spacing elements 90 are coupled to the outside ofone or both of the meshes. The spacing elements are configured suchthat, when the capsules are disposed in the stacked configuration insidethe vaporizer, there is a space between the upper mesh of a capsule andthe lower mesh of the adjacent capsule. The spacing elements are shapedsuch as to perform the aforementioned function without blocking airflowthrough the meshes and/or the plant material, and without interferingwith the contact between electrodes 48 and meshes 84. For someapplications, the spacing element is a single sided adhesive tape. Forsome applications, an anti-adhesive coating material is used as thespacing element. The anti-adhesive coating material is configured toprevent the unused capsules from becoming stuck to one another when theunused capsules are housed in receptacle 40A.

For some applications, central portion 86 of capsule 42 is made of amaterial that has a high heat capacity and/or low heat conductivity sothat it reduces heat loss from the capsule to the surrounding area andreduces heating of the surrounding area during evaporation process. Forsome applications, at least one of the wires of meshes 84 is hollow, anda phase-change material is disposed inside the hollow wire. Thephase-change material reduces heat loss from the capsule, by causing thecapsule to preferentially absorb heat relative to the areas surroundingthe capsule. Alternatively or additionally, a phase change material iscoupled to the capsule is a different manner, e.g., by coating thecapsule. As described hereinabove, typically, the phase-change materialis selected such as to maintain the capsule below the pyrolysistemperature of the plant material, and to thereby prevent the plantmaterial from being pyrolyzed.

Reference is now made to FIG. 5, which is a schematic illustration ofelectrodes 48 of vaporizer 20 in contact with meshes 84 of capsule 42,in accordance with some applications of the present invention. As shown,electrodes 48 contact the meshes even when spacing elements 90 aredisposed upon the outsides of the meshes.

Reference is now made to FIGS. 6A-D, which are schematic illustrationsof respective configurations of electrodes 48 of vaporizer 20, inaccordance with some applications of the present invention. FIG. 6Ashows examples of electrodes 48A and 48B, in accordance with someapplications of the present invention. As shown, for some applications,a surface 92 of the electrode acts as an electrical contact, via whichelectrical contact is made with a mesh of the capsule. FIGS. 6B-D showexamples of electrode 48B, in accordance with respective applications ofthe present invention. For some applications, the electrodes includecontacts 94 that protrude from surface 92 of the electrode. As shown,the contact may be shaped as a flat plate (FIG. 6B), or as a pluralityof points, e.g., two points (FIG. 6C), or three points (FIG. 3D).

Reference is now made to FIGS. 7A-B, which are schematic illustrationsof respective views of vaporizer 20, capsule-transfer mechanism 44 ofthe vaporizer being a linear mechanism, in accordance with someapplications of the present invention.

As shown in FIGS. 7A-B, in accordance with some applications, capsules42 are shaped in a shape that is not circular. For example, as shown inFIGS. 7A-B, the capsule may have a racetrack-shaped cross section. Forsuch applications, receptacles 40A and 40B define hollow spaces that areshaped so as to conform with the shape of the capsules.

For some applications, the top of receptacle 40A, the top of receptacle40B, and the vaporization location, at which the capsules are heated,are aligned with each other (for example, across the width of thevaporizer, as shown in FIGS. 7A-B). A linear capsule-transfer mechanism44 is configured to push unused capsules from receptacle 40A tovaporization location 46 at which the capsule is heated, and from thevaporization location to second receptacle 40B. For some applications,the linear capsule-transfer mechanism includes a pusher 100 that isconfigured to transfer the capsules in the manner described above, bythe pusher being pushed axially in a given direction. For someapplications, a spring 102 is coupled to the pusher, the spring beingconfigured to apply a force to the pusher that opposes movement of thepusher in the given direction.

With reference to FIG. 7B, for some applications, a pump 200 (shownschematically in FIG. 7B) is used to control air flow through thevaporizer. For some applications, the vaporizer is shaped to define asupplementary airflow channel 201, which provides airflow out of themouthpiece, but not via the capsule that is being vaporized. In thismanner, in response to a large inhalation by the user, the vaporizer isable to provide air to the user, without increasing the dosage of theactive ingredient that is provided to the user. For some applications, avalve 203 (shown schematically in FIG. 7B) is disposed within thesupplementary airflow channel and is configured to control airflowthrough the supplementary airflow channel.

For some applications, vaporizer 20 includes an airflow sensor, e.g., avalve 202 (shown schematically in FIG. 7B). The valve is configured tomeasure airflow through the vaporizer. For some applications, themeasured airflow is received as an input to the control circuitry, andthe control circuitry varies a parameter of the heating in response tothe detected airflow.

Apart from the differences described in the above paragraphs, vaporizer20 and portions thereof shown in FIGS. 7A-B are generally similar to thevaporizer and portions thereof described with reference to FIGS. 1A-6D.The scope of the present invention includes combining features of thevaporizer and portions thereof described with reference to FIGS. 7A-B,with features of the vaporizer and portions thereof described withreference to FIGS. 1A-6D, and vice versa.

Reference is now made to FIG. 8, which is a graph illustratingrespective techniques for heating plant material using a vaporizer, suchas vaporizer 20, in accordance with some applications of the presentinvention. The x-axis of the graph indicates time (measured in seconds),and the y-axis indicates the temperature (measured in degrees Celsius)of a capsule that contains a plant material (and therefore indicates thetemperature of the plant material within the capsule), as describedherein.

As described hereinabove, for some applications, vaporizer 20 is used tovaporize active ingredients within Cannabis. Cannabis typically has avaporization temperature of 180 degrees Celsius, and begins to becomepyrolyzed at 220 degrees Celsius. Therefore, it is typically desirableto heat the Cannabis to a temperature of between 190 degrees Celsius and210 degrees Celsius. The upper and lower boundaries of the desiredtemperature range to which to heat Cannabis are denoted on the graph ofFIG. 8, by the two solid horizontal lines at 190 degrees Celsius and 210degrees Celsius. Further typically, it is desirable not to heat theCannabis to a temperature that is greater than the describedtemperature, in order to prevent pyrolysis of the Cannabis. Typically,when the vaporizer is used with plant materials other than Cannabis,similar considerations are applicable, although the desired temperatureto which the plant material should be heated will vary depending on thecharacteristics of the plant material that is being used with thevaporizer.

One possible way of heating the plant material to the desiredtemperature is via gradual heating, as denoted by the dashed diagonalline, which shows the plant material being heated to the desiredtemperature over a period of more than 12 seconds. Another possible wayto heat the plant material is via rapid heating, as denoted by thedotted curve in FIG. 8. Typically, if the plant material is heatedrapidly, then initially there is an overshoot in the temperature towhich the plant material is heated. For example, this may be becausethere is a time lag between when the plant material reaches the desiredtemperature and when the control circuitry detects that the desiredtemperature has been reached and withholds causing further temperatureincrease of the plant material in response to the detected temperature.This is indicated in FIG. 8, which shows that the dotted curve initiallyrises above 220 degrees Celsius, before plateauing within the desiredtemperature range. Due to the overshooting, some of the plant materialmay become pyrolyzed.

In accordance with some applications of the present invention, atwo-stage heating process is applied to plant material within avaporizer, e.g., as indicated by the solid curve shown in FIG. 8.Typically, in response to receiving a first input at the vaporizer(e.g., in response to the user pressing an ON switch on the vaporizer),the control circuitry of the vaporizer initiates a first heating step.Typically, the first heating step is a rapid heating step (e.g., aheating step in which the capsule that contains the plant material isheated at a rate of more than 50 degrees Celsius per second, or morethan 100 degrees Celsius per second). Further typically, the controlcircuitry of the vaporizer is configured to terminate the first heatingstep, by withholding causing further temperature increase of thecapsule, in response to detecting that the temperature of the capsule(which is indicative of the temperature of the plant material) hasreached a first temperature. Typically, the first temperature is lessthan 95 percent, e.g., less than 90 percent, or less than 80 percent, ofthe vaporization temperature of the plant material. For example, whenthe vaporizer is used to vaporize Cannabis, the control circuitry of thevaporizer may be configured to withhold causing further temperatureincrease of the capsule, in response to detecting that the temperatureof the capsule has reached a first temperature that is less than 170degrees Celsius (e.g., less than 160 degrees Celsius), e.g., atemperature that is between 140 and 170 degrees Celsius, or between 150and 160 degrees Celsius.

By configuring the control circuitry to terminate the first, rapidheating stage as described above, even if there is overshoot, and thetemperature of the capsule rises above the temperature at which thefirst heating stage was programmed to be terminated, the temperature ofthe capsule will typically still not rise above the pyrolysistemperature of the plant material. For example, as shown in FIG. 8, thecontrol circuitry has been configured to withhold causing furthertemperature increase of the capsule in response to detecting that thetemperature of the capsule has reached approximately 160 degreesCelsius. Initially (at approximately 1 second), there is an overshoot,and the temperature of the capsule reaches approximately 180 degreesCelsius. However, the temperature of the capsule then reaches a plateauof approximately 160 degrees Celsius, at about 2 seconds. For someapplications, the control circuitry of the vaporizer generates an outputto the user to indicate that the first stage of the heating hasterminated. For example, the control circuitry may illuminate anindicator light, may cause the vaporizer to vibrate, and/or may emit anaudio signal (e.g., a beep).

Subsequently, in response to a second input to the vaporizer, thecontrol circuitry of the vaporizer initiates a second heating step(shown, on the solid curve in FIG. 8, to begin at approximately 4seconds). Typically, between the end of the first stage of the heatingprocess, and the initiation of the second stage of the heating process,the control circuitry maintains the temperature of the capsule at thefirst temperature. For some applications, the second stage of theheating is initiated automatically in response to inhalation of air fromthe vaporizer by a user. Alternatively, the second stage of the heatingprocess may be initiated in response to a different input by the user(e.g., the user pressing the ON button a second time).

During the second heating step, the control circuitry typically heatsthe capsule at a slower rate than during the first stage of the heatingprocess. For example, during the second stage of the heating process,the meshes of the capsules of the vaporizer may be heated at a rate ofless than 50 degrees Celsius per second, e.g., less than 40 degreesCelsius per second. As shown in FIG. 8, during the second stage of theheating process (from 4 seconds to 6 seconds) the capsule is heated fromapproximately 160 degrees Celsius to 200 degrees Celsius.

In the second stage of the heating process, the control circuitry isconfigured to withhold causing further temperature increase of thecapsule in response to detecting that the temperature of the capsule isbetween the vaporization temperature of the plant material and thepyrolysis temperature of the plant material. For example, when thevaporizer is used to vaporize Cannabis, the control circuitry of thevaporizer is configured to withhold causing further temperature increaseof the capsule, in response to detecting that the temperature of thecapsule has reached a second temperature that is more than 180 degreesCelsius (e.g., more than 190 degrees Celsius), and/or less than 220degrees Celsius (e.g., less than 210 degrees Celsius), e.g., atemperature that is between 180 and 220 degrees Celsius, or between 190and 210 degrees Celsius.

For some applications, by performing the heating in the two-stageprocess described hereinabove, one or more of the following results areachieved:

1) By terminating the first (rapid) stage of the heating in response tothe temperature of the capsule reaching less than 95 percent of thevaporization temperature, even if the heating overshoots, the plantmaterial is not pyrolyzed, since the plant material is not heated to atemperature that is greater than the pyrolysis temperature.

2) Since the second stage of the heating is performed slowly, there isnegligible overshooting in the second stage of the heating process, andtherefore the plant material does not get pyrolyzed in the second stageof the heating process.

3) Since, during the first stage of the heating, the plant material hasalready been heated to a temperature that is relatively close thevaporization temperature, even though the second stage of the heating isslow, the time that is required to heat the plant material to thevaporization temperature, from the initiation of the second heatingstage, is relatively short (e.g., less than two seconds).

4) Due to low heat conduction of the plant material, if the plantmaterial is heated rapidly, this can give rise to non-uniform heating ofthe plant material. This can cause portions of the plant material thatare near to the heating element(s) (e.g., the electrode(s)) to bepyrolyzed, and/or portions of the plant material that are further fromthe heating element(s) not to be vaporized. By withholding furtherheating of the plant material after the first temperature has beenreached, and until the second input is received, heat is able todissipate through the plant material (during the interim period betweenthe first and second heating stages) before any portion of the plantmaterial has been heated to the vaporization temperature. Furthermore,since the temperature increase during the second stage is relativelysmall, the temperature increase is able to dissipate through the plantmaterial relatively quickly. Thus, relatively uniform heating of theplant material is achieved, such that most of the active ingredientwithin the plant material is vaporized, while there is substantially nopyrolysis of the plant material.

For some applications, inhalation from the vaporizer by the user isautomatically detected by the control circuitry. After the first stageof the heating, there is typically a large difference between theambient temperature and the temperature of the capsule that contains theplant material. As described hereinabove, between the end of the firststage of the heating process, and the initiation of the second stage ofthe heating process, the control circuitry maintains the temperature ofthe capsule at the first temperature. Since there is a large differencebetween the ambient temperature and the temperature of the capsule, theenergy that is required to maintain the capsule (and the plant materialtherein) at a constant temperature is greater when the user is inhalingfrom the vaporizer than when the user is not inhaling. Therefore, forsome applications, the control circuitry detects that the user isinhaling from the vaporizer by detecting an indication of an amount ofenergy that is required to maintain the temperature of the capsule (andthe plant material therein) constant. For example, the control circuitrymay detect variations in the duty cycle that is used to heat the capsule(and the plant material therein). Alternatively or additionally, thecontrol circuitry may automatically detect that the user is inhalingfrom the vaporizer by directly detecting the temperature of the capsule.Since, after the first stage of the heating, there is a large differencebetween the ambient temperature and the temperature of the capsule,airflow through the capsule may cause a measurable change in thetemperature of the capsule. As described hereinabove, for someapplications, the second stage of the heating process is initiatedautomatically in response to detecting inhalation from the vaporizer bythe user.

Using a generally similar technique to that described hereinabove, forsome applications, the control circuitry detects a rate and/or volume ofair flow through the vaporizer, by detecting an indication of an amountof energy that is required to maintain the temperature of the capsule(and the plant material therein) constant. For some applications, inresponse to the detected rate of air flow through the vaporizer, thecontrol circuitry calculates that dosage of the active substance thathas been administered to the subject. As described hereinabove, for someapplications, a healthcare professional may input instructions into thecontrol circuitry that control the amount of airflow through thevaporizer that is permitted during each use of the vaporizer, and/or theamount of airflow through the vaporizer that is permitted within a giventime period (e.g., per hour, or per day). Alternatively or additionally,the control circuitry may control the heating rate per unit air flow, asdescribed hereinabove.

For some applications, in response to detecting that no inhalation hasoccurred over a given time period (e.g., a time period of between 0.5seconds and 3 seconds), the temperature of the capsule is reduced tobelow the vaporization temperature of the plant material. For example,during use of the vaporizer, the user may stop inhaling for a given timeperiod, due to coughing, and/or due to irritation caused by the plantmaterial. By reducing the temperature to below the vaporizationtemperature, wastage of the active ingredient during this period isreduced, such that the user is able to receive the prescribed dosage ofthe active ingredient.

As indicated by the solid curve in FIG. 8, between approximately 8seconds and 10.5 seconds the control circuitry causes the temperature ofthe capsule to be lowered to below the vaporization temperature. Thismay be performed in response to detecting that no inhalation hasoccurred over a given time period (as described hereinabove), and/or inresponse to a user input (e.g., in response to the user pressing abutton). From approximately 10.5 seconds to 13.5 seconds, the capsule isheated back to the vaporization temperature. This may be performed inresponse to detecting that inhalation has resumed and/or in response toa user input (e.g., in response to the user pressing a button). Betweenapproximately 14.5 seconds and 17 seconds the control circuitry againcauses the temperature of the capsule to be lowered to below thevaporization temperature. This may be performed in response to detectingthat no inhalation has occurred over a given time period, and/or inresponse to a user input (e.g., in response to the user pressing abutton).

Although vaporizer 20 has been described as using resistive heating ofelectrode(s) 48 to heat capsule 42, for some applications, alternativeor additional heating elements and heating techniques are used to heatthe capsule. For example, a laser emitter may act as a heating elementby directing a laser beam at the capsule, in order to heat the capsule.For some applications, a separate heating element that is housed insidethe vaporizer is heated in proximity to the vaporization location, inorder to provide conduction, convection, and/or radiation heating to thecapsule.

For some applications, the vaporizer includes an indicator thatindicates to the user how many unused capsules are housed within thevaporizer. Typically, the vaporizer is configured such that it can onlybe opened and/or refilled by a healthcare professional (e.g., a doctor,or a pharmacist). For some applications, rather than the vaporizer beingconfigured to be refilled, some of the control components of thevaporizer are recyclable and are transferrable to an unused vaporizer,as described hereinabove. For some applications, the size of thecapsules and/or the amount of plant material in each capsule that is tobe provided to a given user may be determined by a healthcareprofessional. In addition, as described hereinabove, the vaporizer istypically programmable, such that only a certain dosage of the activeingredient may be released per use or within a given time period. Inthis manner, if the plant material that is used inside the vaporizer isa regulated substance (e.g., Cannabis), control over the use of thesubstance may be maintained. For some applications, the vaporizer and/orthe capsules include identifying marks or tags (e.g., an RFID or abarcode), such as to facilitate regulation and control of the use of thevaporizer and the capsule.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

1. A capsule, comprising: a first heating element; a second heatingelement; a housing portion sandwiched between the first heating elementand the second heating element, the housing portion defining a cavity; afirst spacing element disposed on the first heating element so as to notoverlap the cavity of the housing portion; and a second spacing elementdisposed on the second heating element so as to not overlap the cavityof the housing portion.
 2. The capsule of claim 1, wherein the firstheating element and the second heating element are planar.
 3. Thecapsule of claim 1, wherein the first heating element and the secondheating element are in a form of a mesh.
 4. The capsule of claim 1,wherein the first heating element and the second heating element defineopenings from 15 to 80 microns.
 5. The capsule of claim 4, wherein thefirst heating element and the second heating element define openingsfrom 20 to 50 microns.
 6. The capsule of claim 1, wherein the housingportion has an annular form.
 7. The capsule of claim 1, wherein aperiphery of each of the first heating element and the second heatingelement is aligned with a periphery of the housing portion.
 8. Thecapsule of claim 1, wherein the first heating element, the secondheating element, and the housing portion are circular and stacked suchthat the capsule has a disk shape.
 9. The capsule of claim 1, whereinthe first heating element, the second heating element, and the housingportion are dimensioned and stacked such that the capsule has at leasttwo linear sides and a curved side connecting the two linear sides. 10.The capsule of claim 9, wherein the capsule has a racetrack shape. 11.The capsule of claim 1, wherein the cavity of the housing portion has acurved section.
 12. The capsule of claim 1, wherein the cavity of thehousing portion is a through hole.
 13. The capsule of claim 1, furthercomprising: a plant material in the cavity of the housing portion. 14.The capsule of claim 13, wherein the plant material includes tobacco.15. The capsule of claim 1, further comprising: a first adhesive betweenthe first heating element and the housing portion; and a second adhesivebetween the second heating element and the housing portion.
 16. Thecapsule of claim 15, wherein the first adhesive and the second adhesiveeach define an opening that corresponds to the cavity of the housingportion with regard to size and shape.
 17. The capsule of claim 1,wherein the first heating element, the second heating element, and thehousing portion are between the first spacing element and the secondspacing element.